Yes. The times have indeed changed.
Remember that at the time the US nuked the civilian population of Japan, the world was a place where things like this were totally acceptable:
I think any country that used a nuclear weapon today would face extremely strong international backlash. Possibly including the US, although we ostensibly still control institutions like the US, IMF, major media, etc.
In 1945 there was no internet to combat lies and propaganda, and most people saw America as the "good guys." That is not the case for Israel, (or even for the US) today. Add to that the hypersensitivity and emotionality of our society and they would really risk a global embargo (outside of their US colony) if they used a nuclear weapon. That, and, as you said, it would not be very effective tactically.